quantum_package/plugins/Orbital_Entanglement/Orbital_Entanglement.irp.f

346 lines
11 KiB
Fortran

use bitmasks
BEGIN_PROVIDER [integer, mo_inp_num]
implicit none
BEGIN_DOC
! This is the number of orbitals involved in the entanglement calculation.
! It is taken equal to the number of active orbitals n_act_orb.
END_DOC
mo_inp_num = n_act_orb
END_PROVIDER
BEGIN_PROVIDER [integer, mo_inp_list, (N_int*bit_kind_size)]
&BEGIN_PROVIDER [integer, mo_inp_list_rev, (mo_tot_num)]
&BEGIN_PROVIDER [integer(bit_kind), mo_inp_bit_list, (N_int)]
implicit none
BEGIN_DOC
! mo_inp_list is the list of the orbitals involved in the entanglement calculation.
! It is taken equal to the list of active orbitals list_act.
! mo_inp_list_rev is a list such that mo_inp_list_rev(mo_inp_list(i))=i.
END_DOC
integer :: i
do i = 1, mo_inp_num
mo_inp_list(i)=list_act(i)
enddo
do i = 1, mo_inp_num
mo_inp_list_rev(mo_inp_list(i))=i
enddo
call list_to_bitstring( mo_inp_bit_list, mo_inp_list, mo_inp_num, N_int)
END_PROVIDER
BEGIN_PROVIDER [double precision, entropy_one_orb, (mo_inp_num)]
&BEGIN_PROVIDER [double precision, entropy_two_orb, (mo_inp_num,mo_inp_num)]
implicit none
BEGIN_DOC
! entropy_one_orb is the one-orbital von Neumann entropy S(1)_i
! entropy_two_orb is the two-orbital von Neumann entropy S(2)_ij.
END_DOC
double precision, allocatable :: ro1(:,:),ro2(:,:,:)
integer :: i,j,k,l,ii,jj,iii,istate,kl,info
integer, allocatable :: occ(:,:)
integer :: n_occ_alpha, n_occ_beta
logical, allocatable :: zocc(:,:)
logical :: zalpha, zbeta, zalpha2, zbeta2
integer :: exc(0:2,2,2),degree,h1,p1,h2,p2,spin1,spin2
double precision :: phase
integer(bit_kind) :: key_tmp(N_int), key_tmp2(N_int)
integer :: ip
double precision, parameter :: eps=10.d0**(-14)
double precision :: w(16), work(3*16)
allocate(ro1(4,mo_inp_num),ro2(16,16,(mo_inp_num*(mo_inp_num-1)/2)))
entropy_one_orb = 0.d0
entropy_two_orb = 0.d0
ro1 = 0.d0
ro2 = 0.d0
allocate (occ(N_int*bit_kind_size,2))
allocate (zocc(mo_tot_num,2))
istate = 1 !Only GS, to be generalized...
do ii=1,N_det
! We get the occupation of the alpha electrons in occ(:,1)
call bitstring_to_list(psi_det(1,1,ii), occ(1,1), n_occ_alpha, N_int)
! We get the occupation of the beta electrons in occ(:,2)
call bitstring_to_list(psi_det(1,2,ii), occ(1,2), n_occ_beta, N_int)
zocc = .false.
do i=1,n_occ_alpha
zocc(occ(i,1),1)=.true.
enddo
do i=1,n_occ_beta
zocc(occ(i,2),2)=.true.
enddo
do k=1,mo_inp_num
zalpha = zocc(mo_inp_list(k),1)
zbeta = zocc(mo_inp_list(k),2)
! mono start
if (zbeta.and.zalpha) then
ro1(4,k) = ro1(4,k) + psi_coef(ii,istate)**2 ! double occupied
elseif (zalpha) then
ro1(2,k) = ro1(2,k) + psi_coef(ii,istate)**2 ! single alpha
elseif (zbeta) then
ro1(3,k) = ro1(3,k) + psi_coef(ii,istate)**2 ! single beta
else
ro1(1,k) = ro1(1,k) + psi_coef(ii,istate)**2 ! empty
endif
! mono stop
! double start
if (k.eq.mo_inp_num) cycle
do l=k+1,mo_inp_num
kl=(l-1)*(l-2)/2+k
zalpha2 = zocc(mo_inp_list(l),1)
zbeta2 = zocc(mo_inp_list(l),2)
if (zbeta.and.zalpha.and.zbeta2.and.zalpha2) then
ro2(16,16,kl) = ro2(16,16,kl) + psi_coef(ii,istate)**2 ! both double occupied
else if (zbeta.and.zalpha.and.zbeta2) then
ro2(15,15,kl) = ro2(15,15,kl) + psi_coef(ii,istate)**2 ! one double, one beta
else if (zbeta.and.zalpha.and.zalpha2) then
ro2(13,13,kl) = ro2(13,13,kl) + psi_coef(ii,istate)**2 ! one double, one alpha
else if (zbeta.and.zbeta2.and.zalpha2) then
ro2(14,14,kl) = ro2(14,14,kl) + psi_coef(ii,istate)**2 ! one beta, one double
else if (zalpha.and.zbeta2.and.zalpha2) then
ro2(12,12,kl) = ro2(12,12,kl) + psi_coef(ii,istate)**2 ! one alpha, one double
else if (zalpha.and.zbeta) then
ro2(11,11,kl) = ro2(11,11,kl) + psi_coef(ii,istate)**2 ! one double, one empty
else if (zbeta2.and.zalpha2) then
ro2(8,8,kl) = ro2(8,8,kl) + psi_coef(ii,istate)**2 ! one empty, one double
else if (zbeta.and.zalpha2) then
ro2(10,10,kl) = ro2(10,10,kl) + psi_coef(ii,istate)**2 ! one beta, one alpha
else if (zalpha.and.zbeta2) then
ro2(9,9,kl) = ro2(9,9,kl) + psi_coef(ii,istate)**2 ! one alpha, one beta
else if (zbeta.and.zbeta2) then
ro2(7,7,kl) = ro2(7,7,kl) + psi_coef(ii,istate)**2 ! one beta, one beta
else if (zalpha.and.zalpha2) then
ro2(6,6,kl) = ro2(6,6,kl) + psi_coef(ii,istate)**2 ! one alpha, one alpha
else if (zbeta) then
ro2(5,5,kl) = ro2(5,5,kl) + psi_coef(ii,istate)**2 ! one beta, one empty
else if (zbeta2) then
ro2(4,4,kl) = ro2(4,4,kl) + psi_coef(ii,istate)**2 ! one empty, one beta
else if (zalpha) then
ro2(3,3,kl) = ro2(3,3,kl) + psi_coef(ii,istate)**2 ! one alpha, one empty
else if (zalpha2) then
ro2(2,2,kl) = ro2(2,2,kl) + psi_coef(ii,istate)**2 ! one empty, one alpha
else
ro2(1,1,kl) = ro2(1,1,kl) + psi_coef(ii,istate)**2 ! both empty
end if
enddo
enddo
! stop double
if (ii.eq.N_det) cycle
!Off Diagonal Elements
do jj=ii+1,N_det
call get_excitation_degree(psi_det(1,1,ii),psi_det(1,1,jj),degree,N_int)
if (degree.gt.2) cycle
ip=0
do iii =1,N_int
key_tmp(iii) = ior(xor(psi_det(iii,1,ii),psi_det(iii,1,jj)),xor(psi_det(iii,2,ii),psi_det(iii,2,jj)))
ip += popcnt(key_tmp(iii))
enddo
if (ip.ne.2) cycle !They involve more than 2 orbitals.
ip=0
do iii=1,N_int
ip += popcnt(iand(key_tmp(iii),mo_inp_bit_list(iii)))
enddo
if (ip.ne.2) cycle !They do not involve orbitals of the list.
if (degree.eq.2) then
call get_double_excitation(psi_det(1,1,ii),psi_det(1,1,jj),exc,phase,N_int)
call decode_exc(exc,degree,h1,p1,h2,p2,spin1,spin2)
k=mo_inp_list_rev(h1)
l=mo_inp_list_rev(p1)
if (k.gt.l) then
kl=(k-1)*(k-2)/2+l
else
kl=(l-1)*(l-2)/2+k
endif
if ((.not.zocc(mo_inp_list(l),1)).and.(.not.zocc(mo_inp_list(l),2))&
.and.(zocc(mo_inp_list(k),1)).and.(zocc(mo_inp_list(k),2))) then
ro2(8,11,kl) += phase*psi_coef(ii,istate)*psi_coef(jj,istate)
ro2(11,8,kl) = ro2(8,11,kl)
endif
if ((zocc(mo_inp_list(l),1)).and.(.not.zocc(mo_inp_list(l),2))&
.and.(.not.zocc(mo_inp_list(k),1)).and.(zocc(mo_inp_list(k),2))) then
ro2(9,10,kl) -= phase*psi_coef(ii,istate)*psi_coef(jj,istate) !negative
ro2(10,9,kl) = ro2(9,10,kl)
endif
if ((zocc(mo_inp_list(k),1)).and.(.not.zocc(mo_inp_list(k),2))&
.and.(.not.zocc(mo_inp_list(l),1)).and.(zocc(mo_inp_list(l),2))) then
ro2(9,10,kl) -= phase*psi_coef(ii,istate)*psi_coef(jj,istate) !negative
ro2(10,9,kl) = ro2(9,10,kl)
endif
endif
if (degree.eq.1) then
call get_mono_excitation(psi_det(1,1,ii),psi_det(1,1,jj),exc,phase,N_int)
call decode_exc(exc,degree,h1,p1,h2,p2,spin1,spin2)
k=mo_inp_list_rev(h1)
l=mo_inp_list_rev(p1)
if (k.gt.l) then
kl=(k-1)*(k-2)/2+l
else
kl=(l-1)*(l-2)/2+k
endif
if ((.not.(zocc(mo_inp_list(l),2))).and.&
(.not.(zocc(mo_inp_list(l),1))).and.(zocc(mo_inp_list(k),1))&
.and.(.not.(zocc(mo_inp_list(k),2)))) then
ro2(2,3,kl) += phase*psi_coef(ii,istate)*psi_coef(jj,istate)
ro2(3,2,kl)=ro2(2,3,kl)
endif
if ((.not.(zocc(mo_inp_list(l),2))).and.&
(.not.(zocc(mo_inp_list(l),1))).and.(zocc(mo_inp_list(k),2))&
.and.(.not.(zocc(mo_inp_list(k),1)))) then
ro2(4,5,kl) += phase*psi_coef(ii,istate)*psi_coef(jj,istate)
ro2(5,4,kl)=ro2(4,5,kl)
endif
if ((.not.(zocc(mo_inp_list(l),1))).and.& !k doubly occupied, l empty
(.not.(zocc(mo_inp_list(l),2))).and.&
(zocc(mo_inp_list(k),1)).and.&
(zocc(mo_inp_list(k),2))) then
if (k.gt.l) then
if (spin1.eq.1) then !spin alpha
ro2(8,9,kl) += phase*psi_coef(ii,istate)*psi_coef(jj,istate)
ro2(9,8,kl)=ro2(8,9,kl)
else !spin beta
ro2(8,10,kl) -= phase*psi_coef(ii,istate)*psi_coef(jj,istate) !negative
ro2(10,8,kl)=ro2(8,10,kl)
endif
else ! k.lt.l
if (spin1.eq.1) then !spin alpha
ro2(10,11,kl) -= phase*psi_coef(ii,istate)*psi_coef(jj,istate) !negative
ro2(11,10,kl)=ro2(10,11,kl)
else !spin beta
ro2(9,11,kl) += phase*psi_coef(ii,istate)*psi_coef(jj,istate)
ro2(11,9,kl)=ro2(9,11,kl)
endif
endif
endif
if ((.not.(zocc(mo_inp_list(l),1))).and.& !k alpha, l beta
(.not.(zocc(mo_inp_list(k),2))).and.&
(zocc(mo_inp_list(k),1)).and.&
(zocc(mo_inp_list(l),2))) then
if (k.gt.l) then
if (spin1.eq.1) then !spin alpha
ro2(10,11,kl) -= phase*psi_coef(ii,istate)*psi_coef(jj,istate) !negative
ro2(11,10,kl)=ro2(10,11,kl)
else !spin beta
print*, "problem in k alpha l beta k.gt.l spin beta"
endif
else ! k.lt.l
if (spin1.eq.1) then !spin alpha
ro2(8,9,kl) += phase*psi_coef(ii,istate)*psi_coef(jj,istate)
ro2(9,8,kl)=ro2(8,9,kl)
else !spin beta
print*, "problem in k alpha l beta k.lt.l spin beta"
endif
endif
endif
if ((.not.(zocc(mo_inp_list(k),1))).and.& !k beta, l alpha
(.not.(zocc(mo_inp_list(l),2))).and.&
(zocc(mo_inp_list(l),1)).and.&
(zocc(mo_inp_list(k),2))) then
if (k.gt.l) then
if (spin1.eq.2) then !spin beta
ro2(9,11,kl) += phase*psi_coef(ii,istate)*psi_coef(jj,istate)
ro2(11,9,kl)=ro2(9,11,kl)
else !spin alpha
print*, "problem in k beta l alpha k.gt.l spin alpha"
endif
else ! k.lt.l
if (spin1.eq.2) then !spin beta
ro2(8,10,kl) -= phase*psi_coef(ii,istate)*psi_coef(jj,istate) !negative
ro2(10,8,kl)=ro2(8,10,kl)
else !spin alpha
print*, "problem in k beta l alpha k.lt.l spin alpha"
endif
endif
endif
if (zocc(mo_inp_list(l),1).and.(.not.zocc(mo_inp_list(l),2))&
.and.(zocc(mo_inp_list(k),1)).and.(zocc(mo_inp_list(k),2))) then
ro2(12,13,kl) -= phase*psi_coef(ii,istate)*psi_coef(jj,istate)
ro2(13,12,kl) = ro2(12,13,kl)
endif
if (zocc(mo_inp_list(l),2).and.(.not.zocc(mo_inp_list(l),1))&
.and.(zocc(mo_inp_list(k),1)).and.(zocc(mo_inp_list(k),2))) then
ro2(14,15,kl) -= phase*psi_coef(ii,istate)*psi_coef(jj,istate)
ro2(15,14,kl) = ro2(14,15,kl)
endif
endif
enddo
enddo
entropy_one_orb=0.d0
do k=1,mo_inp_num
do i=1,4
if (ro1(i,k).ge.eps) then
entropy_one_orb(k) = entropy_one_orb(k)-ro1(i,k)*log(ro1(i,k))
endif
enddo
enddo
entropy_two_orb=0.d0
do k=1,mo_inp_num
do l=1,k
if (k.eq.l) cycle
kl=(k-1)*(k-2)/2+l
call dsyev('N','U',16,ro2(1,1,kl),16,w,work,3*16,info)
if (info.ne.0) then
write(*,*) "Errore in dsyev"
endif
do j=1,16
if (w(j).ge.eps) then
entropy_two_orb(k,l) = entropy_two_orb(k,l)-w(j)*log(w(j))
entropy_two_orb(l,k) = entropy_two_orb(k,l)
elseif ((w(j)).lt.(-eps)) then
write(6,*) "Negative Eigenvalue. You have a big problem..."
write(6,*) w(j)
stop
endif
enddo
enddo
enddo
deallocate (occ,zocc,ro1,ro2)
END_PROVIDER
BEGIN_PROVIDER [double precision, mutinf, (mo_inp_num,mo_inp_num)]
implicit none
BEGIN_DOC
!mutinf is the mutual information (entanglement), calculated as I_ij=0.5*[S(1)_i+S(1)_j-S(2)_ij]
!see the refence: 10.1016/j.chemphys.2005.10.018
END_DOC
integer :: i,j
! mutal information:
mutinf = 0.d0
do i=1,mo_inp_num
do j=1,mo_inp_num
if (j.eq.i) cycle
mutinf(i,j)=-0.5d0*(entropy_two_orb(i,j)-entropy_one_orb(i)-entropy_one_orb(j))
enddo
enddo
END_PROVIDER